Stable Suspensions Containing Microcapsules and Methods for Preparation Thereof

ABSTRACT

A stable suspension for the production of a temperature-regulating, polymer-containing material or fabric, comprises a solvent and a plurality of microcapsules containing at least one phase-change material. The microcapsules are incorporated in the polymer-containing material, and the stable suspension is characterized in that the solvent is capable of dissolving a fabric-forming component selected from the group consisting of at least one of the polymer and precursors thereof and the suspension is stable for at least about 20 hours. A method for manufacturing a suspension comprising a solvent and a plurality of microcapsules containing at least one phase-change material comprises providing microcapsules containing a phase-change material, providing a solvent capable of dissolving a fabric-forming component selected from the group consisting of at least one of the polymer and precursors thereof, and mixing the solvent and the microcapsules to form the suspension.

PRIORITY CLAIM AND CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Israeli Patent Application No.176693 filed on Jul. 4, 2006, and PCT Patent Application No.PCT/US2007/71373 filed on Jun. 15, 2007. The disclosure and all detailsof these prior applications are incorporated herein by reference intheir entirety and for all proper purposes. This application is alsorelated to Taiwan Patent Application No. 096121906 filed on Jun. 15,2007, the details of which are also incorporated by reference into thepresent application in its entirety and for all proper purposes.

FIELD OF THE INVENTION

Aspect of the present invention relate generally to temperatureregulating fabrics. More particularly, aspects of the present inventionrelate to a stable suspension used for the production of such fabricthat includes microcapsules comprising at least one phase-changematerial.

BACKGROUND OF THE INVENTION

The human body maintains its temperature at a constant level, by use ofthe sweating process for cooling and body hair as an isolation medium.However, the natural human body temperature adjusting capabilities arelimited, and are disturbed by clothing.

Temperature-regulating material, such as phase-change material, whenplaced near the body can help regulate skin and microclimatetemperatures. Phase-change material with a phase-changing temperature ina desired range, absorbs energy from the skin as the body temperaturerises, and releases heat to the body as the body cools down. Thisresults in less fluctuation in the human skin and microclimatetemperatures, a greater feeling of comfort, less sweating, and lowermicroclimate relative humidity.

Phase-change material can also function as an energy saver, e.g., if aroom is furnished with an element containing phase-change material, suchas paints, carpets, furniture finish, furniture fabrics or furniturecoating, the element absorbs excessive heat during the warmer hours, andreleases it during cooler hours. In a similar manner, it may also beused in building and construction materials such as insulation, roofing,wallboards, wallcoverings, ceiling materials, floor and floor coveringmaterials, etc. Furthermore, phase-change materials may also be used innumerous other markets where temperature regulation, or temperaturebuffering, may have a benefit, such as: healthcare, apparel,electronics, transportation, shipping, cosmetics/personal care, food andbeverage packaging, appliances, disposables and more.

In general, a temperature-regulating material may comprise any substance(or mixture of substances) that has the capability of absorbing orreleasing thermal energy to reduce or eliminate heat flow at or within atemperature stabilizing range. The temperature stabilizing range maycomprise a particular transition temperature or range of transitiontemperatures. A phase-change material, if properly located in the finalproduct, is capable of inhibiting a flow of thermal energy during a timewhen the phase-change material is absorbing or releasing heat, typicallyas the phase-change material undergoes a transition between two states(e.g., liquid and solid states, liquid and gaseous states, solid andgaseous states, or two solid states). This action is typicallytransient, e.g., occurs until a latent heat of the phase-change materialis absorbed or released during a heating or cooling process. Thermalenergy may be stored or removed from the phase-change material, and thephase-change material typically can be effectively recharged by a hot orcold source.

Phase-change material normally is encapsulated. Encapsulation is desiredfor some of the following reasons: protection against leakage of thephase-change material after the phase-change to a liquid state; andprotection of phase-change material from contamination, increaseddurability; product feel, etc.

For some applications, e.g., clothing, the capsules may be in themicrometer/nanometer size range. In these size ranges, the phase-changematerial capsules can be incorporated into a product without change inthe appearance, texture or production process of the product. Capsulesin the micrometer/nanometer size range are referred to here asmicrocapsules. Phase-change material encapsulated with microcapsules isreferred to as microencapsulated phase-change material (mPCM)

Microencapsulated phase-change material can be introduced intocommercial products in various ways. According to some industrialpractices, mPCM, typically in combination with binders, and possiblyother components, is coated on commercial products. Coating may useknown methods, such as knife-over-roll coating, roll coating, slotcoating, screenprinting, foam coating, laminating, exhausting, spraying,padding, extrusions, embossing or flocking e.g. as described in U.S.Pat. Nos. 5,366,801; 6,207,738; 6,217,993; 6,503,976; 6,514,362; and6,660,667, the relevant teachings of which are incorporated herein byreference.

Many commercial products are made of fibers. Microencapsulatedphase-change material can be coated on fibers prior to conversion to thefinal commercial product or after it. Alternatively, mPCM may beincorporated into the fibers in the process of their manufacture.

Conventionally, two processes are used to manufacture synthetic fibers:a solution spinning process and a melt spinning process. The solutionspinning process is generally used to form acrylic or regeneratedcellulosic fibers, while the melt spinning process is generally used toform nylon fibers, polyester fibers, polypropylene fibers, and othersimilar type fibers. The solution spinning process is divided into twomain spinning techniques; dry spinning and wet spinning. In the wetspinning process the spinnerets are submerged in or held very close to achemical bath and as the filaments emerge they contact the chemical bathand precipitate from solution and solidify. In the dry spinning processinstead of precipitating the polymer by dilution or chemical reaction,solidification is achieved by evaporating the solvent in a stream of airor inert gas which can be heated or cooled.

Several methods have been developed for the incorporation ofphase-change material and microencapsulated phase-change material intofibers, as described for example in U.S. Pat. Nos. 6,855,422; 6,689,466;and 4,756,958 and US Patent Applications 20050208300; 20040126555;20020054964, and in Acrylic Fibers by R. Cox in Synthetic Fibers: Nylon,Polyester, Acrylic, Polyolefins, Woodhead Publishing ISBN 1 85573 588 1,the relevant teachings of which are incorporated here by reference. Manyof these methods suffer from a common difficulty related to thedispersion of the microencapsulated phase-change material (mPCM). Duringthe process of fiber manufacture, the incorporated microcapsules tend toform agglomerates of larger particles. This agglomeration may lead tomanufacturing and yield problems and to the production of unattractivemPCM-containing fibers. Particularly affected are the physicalproperties of the fiber such as strength, denier variation, thick andthin spots, etc. If microcapsules agglomerate, production problems suchas filter blockage, deposition on pipe walls, pressure and flowvariations and spinneret hole blockage may occur. This further causeschanges in fiber denier and or production line stoppage.

In some of the manufacturing processes, a suspension of mPCM in asolution is produced and then mixed with a solution of a polymer or of apolymer-precursor (e.g. monomer) for spinning. The manufacturing processis simplified if a suspension of mPCM is formed in a way that is stableenough to enable storage prior to mixing with the polymer (or precursor)for a prolonged period with no substantial agglomeration or phaseseparation. Furthermore, after mixing, the mPCM should be evenlydispersed in the mixture to enable the production of fibers with desireddistribution of mPCM. Achieving such desired stable suspensions and evendispersion is difficult in many cases, e.g. due to the high ionicstrength of the solution. In many cases “creaming” is observed. Thisterm is used to describe the formation of two layers, with themicrocapsules presiding in the top layer. If creaming occurs in pipework, it forms a skin or coating on the pipe work which is verydifficult to remove.

SUMMARY OF THE INVENTION

Thus according to one aspect, a stable first suspension for theproduction of a temperature-regulating, polymer-containing fabriccomprises a solvent and a plurality of microcapsules containing at leastone phase-change material, wherein the microcapsules are adapted to beincorporated in the polymer-containing fabric, and wherein the stablefirst suspension is characterized in that the solvent is capable ofdissolving a fabric-forming component selected from the group consistingof at least one of the polymer and precursors thereof, and thesuspension is stable for at least about 20 hours.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphic representation of particle size distribution of afreshly formed stable suspension of microcapsules; and

FIG. 2 is a graphic representation of particle size distribution of astable suspension of microcapsules.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein the term “stable suspension” can refer, for example, to asuspension wherein a plurality of microcapsules comprising phase-changematerial is suspended in a solvent and wherein the majority of themicrocapsules are evenly dispersed. The term can also refer to asuspension, wherein the majority of the microcapsules are notsubstantially agglomerated. The term can also refer to a suspension,wherein the majority of the microcapsules do not float on top of thesolvent nor sink to its bottom. The term can also refer to a suspension,wherein no creaming takes place. Combinations of the above are alsocontemplated within the term “stable suspension.”

As used herein the term “polymer precursor” refers, for example, tocompounds that are converted to a polymer by polymerization, optionallywith other compounds. Monomers are examples of polymer precursors.

As used herein the term “evenly dispersed” refers, for example, to astate where the majority of the microcapsules are not agglomerated.

As used herein the term “solvent capable of dissolving” refers, forexample, to a solvent wherein the polymer or its precursor is soluble tothe extent that a solution containing at least 1 weight percent of thesolute can be prepared.

As used herein, the term “latent heat” refers, for example, to thequantity of energy absorbed or released by a substance undergoing achange of state.

As used herein, the term “phase-change material” refers, for example, toa material that has the capability of absorbing or releasing energy toadjust heat transfer at or within a temperature stabilizing range. Atemperature stabilizing range can include a specific transitiontemperature or a range of transition temperatures. In some instances, aphase-change material can be capable of inhibiting heat transfer duringa period of time when the phase-change material is absorbing orreleasing heat, typically as the phase-change material undergoes atransition between two states. This action is typically transient andwill occur until a latent heat of the phase-change material is absorbedor released during a heating or cooling process. Heat can be stored orremoved from a phase-change material, and the phase-change materialtypically can be effectively recharged by a source of heat or cold. Forcertain implementations, a phase-change material can be a mixture of twoor more materials. By selecting two or more different materials andforming a mixture, a temperature stabilizing range can be adjusted forany desired application. The resulting mixture can exhibit two or moredifferent transition temperatures or a single modified transitiontemperature when incorporated in accordance with the following articles.

-   “A Review on Phase-change Energy Storage: Materials and    Applications” by Farid, M. M., et. al in Energy Conversion and    Management 45, (2004) 1597-1615.-   “Review on Thermal Energy Storage with Phase-change: Materials, Heat    Transfer Analysis and Applications” by Zalba, B., et. al in Applied    Thermal Engineering I 23 (2003), 251-283.-   “Actual Problems in Using Phase-Change Materials to Store Solar    Energy” by Kenisarin, M., et. al, Paper presented at the NATO    Advanced Study Institute Summer School on Thermal Energy Storage for    Sustainable Energy Consumption (TESSEC), Cesme, Izmir, Turkey, June,    2005.

Phase-change materials that can benefit from stabilization include avariety of organic substances. Exemplary phase-change materials include,by way of example and not by limitation, hydrocarbons (e.g., straightchain alkanes or paraffinic hydrocarbons, branched-chain alkanes,unsaturated hydrocarbons, halogenated hydrocarbons, and alicyclichydrocarbons), fatty acids, fatty acid esters, dibasic acids, dibasicesters, 1-halides, primary alcohols, aromatic compounds, anhydrides(e.g., stearic anhydride), ethylene carbonate, glycols, polyhydricalcohols (e.g., 2,2-dimethyl-1,3-propanediol,2-hydroxymethyl-2-methyl-1,3-propanediol, polyethylene gylcol,pentaerythritol, dipentaerythrital, pentaglycerine), polymers,polyglycols metals, and mixtures thereof.

The selection of the phase-change material can be dependent upon alatent heat and a transition temperature of the phase-change material. Alatent heat of the phase-change material typically correlates with itsability to reduce or eliminate heat transfer. In some instances, thephase-change material can have a latent heat that is at least about 40J/g, such as at least about 50 J/g, at least about 60 J/g, at leastabout 70 J/g, at least about 80 J/g, at least about 90 J/g, or at leastabout 100 J/g. Thus, for example, the phase-change material can have alatent heat ranging from about 40 J/g to about 400 J/g, preferably fromabout 60 J/g to about 400 J/g, from about 80 J/g to about 400 J/g, orfrom about 100 J/g to about 400 J/g. A transition temperature of thephase-change material typically correlates with a desired temperature ora desired range of temperatures that can be maintained by thephase-change material. In some instance, the phase-change material canhave a transition temperature ranging from about −10° C. to about 110°C., such as from about 0° C. to about 100° C., from about 0° C. to about50° C., from about 10° C. to about 50° C., from about 15° C. to about45° C., from about 22° C. to about 40° C., or from 22° C. to about 28°C. The selection of the phase-change material can be dependent uponother considerations, such as its reactivity or lack of reactivity witha material forming the shells, its resistance to degradation underambient or processing conditions, its biodegradability, and itstoxicity.

Table 1 provides a list of exemplary paraffinic hydrocarbons that may beused as the phase-change material stabilized in the accordance withvarious embodiments.

TABLE 1 No. of Melting Paraffinic Hydrocarbon Carbon Atoms Point ° C.n-Octacosane 28 61.4 n-Heptacosane 27 59.0 n-Hexacosane 26 56.4n-Pentacosane 25 53.7 n-Tetracosane 24 50.9 n-Tricosane 23 47.6n-Docosane 22 44.4 n-Heneicosane 21 40.5 n-Eicosane 20 36.8 n-Nonadecane19 32.1 n-Octadecane 18 28.2 n-Heptadecane 17 22.0 n-Hexadecane 16 18.2n-Pentadecane 15 10.0 n-Tetradecane 14 5.9 n-Tridecane 13 −5.5

A phase-change material can be a mixture of two or more substances(e.g., two or more of the exemplary phase-change materials discussedabove). By selecting two or more different substances (e.g., twodifferent paraffinic hydrocarbons) and forming a mixture thereof, atemperature stabilizing range can be adjusted over a wide range for anydesired application. According to some embodiments, a phase-changematerial may comprise a copolymer of two or more substances (e.g., twoor more of the exemplary phase-change materials discussed above).

The selection of a phase-change material will typically be dependentupon a desired transition temperature or a desired application of aresulting multi-component fiber. For example, a phase-change materialhaving a transition temperature near room temperature may be desirablefor applications in which the resulting multi-component fiber isincorporated into apparel designed to maintain a comfortable temperaturefor a user.

According to other embodiments, phase-change materials includeparaffinic hydrocarbons having between 10 to 44 carbon atoms (i.e.,C₁₀-C₄₄ paraffinic hydrocarbons). Table 1 provides a list of exemplaryC₁₃-C₂₈ paraffinic hydrocarbons that may be used as the phase-changematerial in the silica capsules described herein. The number of carbonatoms of a paraffinic hydrocarbon typically correlates with its meltingpoint. For example, n-Octacosane, which contains twenty-eight straightchain carbon atoms per molecule, has a melting point of 61.4° C. Bycomparison, n-Tridecane, which contains thirteen straight chain carbonatoms per molecule, has a melting point of −5.5° C. According to oneembodiment, n-Octadecane, which contains eighteen straight chain carbonatoms per molecule and has a melting point of 28.2° C., is useful forclothing applications.

Other useful phase-change materials include polymeric phase-changematerials having transition temperatures suitable for a desiredapplication of the multi-component fiber (e.g., from about 22° C. toabout 40° C. for clothing applications). A polymeric phase-changematerial may comprise a polymer (or mixture of polymers) having avariety of chain structures that include one or more types of monomerunits. In particular, polymeric phase-change materials may includelinear polymers, branched polymers (e.g., star branched polymers, combbranched polymers, or dendritic branched polymers), or mixtures thereof.A polymeric phase-change material may comprise a homopolymer, acopolymer (e.g., terpolymer, statistical copolymer, random copolymer,alternating copolymer, periodic copolymer, block copolymer, radialcopolymer, or graft copolymer), or a mixture thereof. As one of ordinaryskill in the art will understand, the reactivity and functionality of apolymer may be altered by addition of a functional group such as, forexample, amine, amide, carboxyl, hydroxyl, ester, ether, epoxide,anhydride, isocyanate, silane, ketone, and aldehyde. Also, a polymercomprising a polymeric phase-change material may be capable ofcrosslinking; entanglement; or hydrogen bonding in order to increase itstoughness or its resistance to heat, moisture, or chemicals.

According to other embodiments, a polymeric phase-change material may bedesired which has a higher molecular weight, larger molecular size, orhigher viscosity relative to a non-polymeric phase-change material(e.g., paraffinic hydrocarbons). As a result of this larger molecularsize or higher viscosity, a polymeric phase-change material may exhibita lesser tendency to leak from its shell, for example, the largermolecular size or higher viscosity may prevent the polymericphase-change material from flowing through a sheath member or sealmember forming the exterior of the shell.

For example, polyethylene glycols may be used as the phase-changematerial in some embodiments. The average molecular weight of apolyethylene glycol typically correlates with its melting point. Forinstance, a polyethylene glycol having an average molecular weight rangeof 570 to 630 (e.g., Carbowax 600) will have a melting point of 20° C.to 25° C. Other polyethylene glycols that may be useful at othertemperature stabilizing ranges include Carbowax 400 (melting point of 4°C. to 8° C.), Carbowax 1500 (melting point of 44° C. to 48° C.), andCarbowax 6000 (melting point of 56° C. to 63° C.). Polyethylene oxideshaving a melting point in the range of 60° C. to 65° C. may also be usedas phase-change materials in some embodiments. Further desirablephase-change materials include polyesters having a melting point in therange of 0° C. to 40° C., that may be formed, for example, bypolycondensation of glycols (or their derivatives) with diacids (ortheir derivatives). Table 2 sets forth melting points of exemplarypolyesters that may be formed with various combinations of glycols anddiacids.

TABLE 2 Melting Point of Glycol Diacid Polyester (° C.) Ethylene glycolCarbonic 39 Ethylene glycol Pimelic 25 Ethylene glycol Diglycolic 17-20Ethylene glycol Thiodivaleric 25-28 1,2-Propylene glycol Diglycolic 17Propylene glycol Malonic 33 Propylene glycol Glutaric 35-39 Propyleneglycol Diglycolic 29-32 Propylene glycol Pimelic 37 1,3-butanediolSulphenyl divaleric 32 1,3-butanediol Diphenic 36 1,3-butanediolDiphenyl 38 methane-m,m′-diacid 1,3-butanediol trans-H,H-terephthalicacid 18 Butanediol Glutaric 36-38 Butanediol Pimelic 38-41 ButanediolAzelaic 37-39 Butanediol Thiodivaleric 37 Butanediol Phthalic 17Butanediol Diphenic 34 Neopentyl glycol Adipic 37 Neopentyl glycolSuberic 17 Neopentyl glycol Sebacic 26 Pentanediol Succinic 32Pentanediol Glutaric 22 Pentanediol Adipic 36 Pentanediol Pimelic 39Pentanediol para-phenyl diacetic acid 33 Pentanediol Diglycolic 33Hexanediol Glutaric 28-34 Hexanediol 4-Octenedioate 20 HeptanediolOxalic 31 Octanediol 4-Octenedioate 39 Nonanediol meta-phenylenediglycolic 35 Decanediol Malonic 29-34 Decanediol Isophthalic 34-36Decanediol meso-tartaric 33 Diethylene glycol Oxalic 10 Diethyleneglycol Suberic 28-35 Diethylene glycol Sebacic 36-44 Diethylene glycolPhthalic 11 Diethylene glycol trans-H,H-terephthalic acid 25 Triethyleneglycol Sebacic 28 Triethylene glycol Sulphonyl divaleric 24 Triethyleneglycol Phthalic 10 Triethylene glycol Diphenic 38 para-dihydroxy-methylMalonic 36 benzene meta-dihydroxy-methyl Sebacic 27 benzenemeta-dihydroxy-methyl Diglycolic 35 benzene

According to some embodiments, a polymeric phase-change material havinga desired transition temperature may be formed by reacting aphase-change material (e.g., an exemplary phase-change materialdiscussed above) with a polymer (or mixture of polymers). Thus, forexample, n-octadecylic acid (i.e., stearic acid) may be reacted oresterified with polyvinyl alcohol to yield polyvinyl stearate, ordodecanoic acid (i.e., lauric acid) may be reacted or esterified withpolyvinyl alcohol to yield polyvinyl laurate. Various combinations ofphase-change materials (e.g., phase-change materials with one or morefunctional groups such as amine, carboxyl, hydroxyl, epoxy, silane,sulfuric, and so forth) and polymers may be reacted to yield polymericphase-change materials having desired transition temperatures.

A phase-change material can comprise a mixture of two or more substances(e.g., two or more of the exemplary phase-change materials discussedabove). By selecting two or more different substances (e.g., twodifferent paraffinic hydrocarbons) and forming a mixture thereof, atemperature stabilizing range can be adjusted over a wide range for anyparticular application. According to some embodiments, the mixture oftwo or more different substances may exhibit two or more distincttransition temperatures or a single modified transition temperature.

According to another embodiment, the microcapsules comprise a shell anda core. According to another embodiment, the core comprises phase-changematerial. The shell provides at least one of encapsulating, containing,surrounding and absorbing the phase-change material. This shell mayfacilitate handling of the phase-change material while offering a degreeof protection to the phase-change material during manufacture of thefibers (e.g., protection from high temperatures or shear forces).Various materials are suitable for the microcapsules shells, includingsynthetic polymers, such as formaldehyde-based ones, isocyanate, amines,carboxylic acid derivatives, natural materials such as gelatin orcellulose and acrylic polymers, and others such as silica. The shellpolymers can be thermoplastic or thermoset, crosslinked oruncrosslinked, soft or hard, flexible or rigid. According to anotherembodiment, the shell is formed from formaldehyde-based polymers, silicaparticles, or acrylic polymers precursors such as acrylic acid,methacrylic acid, formaldehyde and a silica precursor, such as describedin patents EP1321182 and U.S. Pat. No. 6,716,526 and patent applicationsWO2004092299 and WO2005105291, the details of which are incorporated byreference in their entirety into the present disclosure.

The stable suspension comprises a solvent capable of dissolving apolymer to be included in a temperature-regulating fabric, or capable ofdissolving a precursor of such polymer. Any polymer is suitable if it isincorporated in such temperature-regulating fabric. According to anotherembodiment, the polymer is at least one of acrylonitrile-based polymersand cellulose-based polymer. Any solvent capable of dissolving thepolymer to be incorporated or its precursor is suitable. According toanother embodiment the solvent is an aqueous solution. According toanother embodiment the aqueous solution comprises at least one solute,such as sodium base, sodium thiocyanate, zinc chloride, acetone, DMF,NMP and nitric acid. According to an another embodiment the soluteconcentration in the solvent on microcapsules-free basis is in a rangeof between about 0.5 percent and about 90 percent by weight. Accordingto another embodiment the solute concentration in the solvent onmicrocapsules-free basis is in a range of between about 1 percent andabout 70 percent by weight.

The stable suspension comprises the solvent and the phase-changematerial-comprising microcapsules. According to another embodiment themicrocapsules form between about 5 and about 50 percent by weight of thesuspension. According to another embodiment the microcapsules formbetween about 10 and about 30 percent by weight of the suspension.

One potential characteristic of the stable suspension comprising thesolvent and the microcapsules is that it is stable for at least 20hours. According to another embodiment, the stable suspension is stablefor at least 40 hours. As described above, the term “stable suspension”may refer to a suspension wherein the majority of the microcapsules areevenly dispersed, such as a state where the majority of themicrocapsules are not agglomerated. The term “stable suspension” mayalso refer to a suspension, wherein the majority of the microcapsulesare not agglomerated. The term may also refer to a suspension, whereinthe majority of the microcapsules do not float on top of the solvent norsink to its bottom. The term may also refer to a suspension, wherein nocreaming is observed.

According to another embodiment, the stable suspension comprises anadditive selected from a group consisting of defoaming agents, wettingagents, flow-control agents, dispersing agents and surfactants. Suitableadditives include:

-   -   a) Flow control and Theological agents, such as water soluble        polymers, water insoluble polymers, clays, microcrystalline        cellulose aerosols;    -   b) Dispersing agents, such as anionic, cationic, amphoteric and        nonionic surfactants, derivatives of polyacrylic acids, low or        high molecular weight unsaturated acidic polycarboxylic acid        polyester, polyquaternary ammonium compounds, polycarboxylic        acids, salts of long chain polyamine amides, and alkylolammonium        salt of a block copolymer with acidic groups;    -   c) Wetting agents, such as polyether modified        poly-dimethyl-siloxane (such as BYK-348, BYK-346, BYK-333 from        Byk Chemie).

In general, the wetting agents may be selected from a group consistingof silicon compounds, fluorine compounds, polyglycols, fatty acids,fatty amides, fatty alcohols and their esters and ethers. Suitableagents can also comprises various mixtures, blends and copolymers fromthe above list.

In various embodiments the first suspension further comprises at leastone compound with some functional aspect, which may include, forexample, fire retardation, bioactivity, antimicrobial activity, odorresistance, UV absorption, moisture management and resistance to water,grease, dirt and/or stain. According to another embodiment, functionalcompounds and functionality are selected from a group consisting ofthose set forth in Table 3 as well as any similar or related functions.

TABLE 3 Textile Property and Materials that Provide that BenefitFunctionality Functional compounds Moisture Hydrophilic and polarmaterials such as acids, hydroxyl, ethers, esters, Management amines,amides imines, urethanes, sulfones, sulfides, natural saccharides, andgrease cellulose, sugars, proteins, etc. Example materials are glycols,polyethylene resistance glycols, acids, salts, and natural hydroxylcontaining materials Water resistance, Nonfunctional, nonpolar andhydrophobic materials such as fluorinated dirt resistance, compounds,silicon compounds, hydrocarbons, polyolefins, fatty acids, etc. andstain resistance Fire Halogenated compounds, especially compoundscontaining Chlorine or retardants Bromine. Phosphorus containingcompounds, High Nitrogen-low oxygen containing compounds and metals suchas antimony, etc. Anti- Complexing metallic compounds based on metalslike silver, Zinc and microbial, copper, which cause inhibition of theactive enzyme centers. Copper and anti-fungal copper salts (Cu⁺², Cu⁺)containing materials such as those provided by and anti- Cupron Corp.Greensboro, NC. bacterial Silver and Silver salt containing materialsand monomers (Ag, Ag⁺, Ag⁺²) such Ultra-Fresh ® from Thomson ResearchAssoc. Inc.; Sanitized ® Silver and Zinc from Clariant Corp. Oxidizingagents such as aldehydes, halogens and proxy compounds attack the cellmembranes. Products such as HaloShield ® from Vanson HaloSource Inc. Oneof the most durable anti-microbials is 2,4,4′-trichloro-2′-hydroxydipenyl ether (Triclosan ®). Triclosan inhibits growth of microorganismsby using an electro-chemical mode of action to penetrate and disrupttheir cell walls. Quaternary ammonium compounds, biguanides, amines andglucoprotamine. Fibres finished with these substances bind microorganisms to their cell membrane and disrupt the lipo polysaccharidestructure resulting in the breakdown of the cell. Products such asquaternary ammonium silanes from Aegis Environments, or Sanitized ® QuatT99-19 from Clariant Corp.; biguanides under the Purista ® brand fromAvecia Inc., Another aspect is the attachment of quaternary ammoniumcompounds as outlined in EP1115940. These compounds can be attachedthrough acid groups on the polymeric PCM polymer, acidic groups on themicrocapsule shell, or acid groups on the textile substrate. Chitosan isan effective natural antimicrobial agent derived from Chitin, a majorcomponent in crustacean shells. Castor oil derivatives based onUndecylene acid or Undecynol. Products such as Undecylenoxy polyethyleneglycol acrylate or methacrylate.

According to one embodiment, the functional compound is dissolved in thestable suspension. According to another embodiment, the functionalcompound is encapsulated in shells. According to a related embodiment,the shell is similar in properties to the shells of the phase-changematerial microcapsules. According to another embodiment, the shell ofthe functional-compound microcapsules is made of the same material asthe shell of phase-change material microcapsules. According to a relatedembodiment, the functional compound is encapsulated and themicrocapsules are evenly dispersed in the stable suspension.

According to another embodiment, the stable suspension is kept at acontrolled temperature. According to a related embodiment, thattemperature is in the range between about 15° C. and about 120° C.According to another embodiment, the temperature is kept at atemperature between about 20° C. and about 50° C. According to anotherembodiment, the stable suspension is kept under low-shear mixing.According to an embodiment of the solution, low-shear mixing is mixingor agitation with paddles or propellers at shear rates of 1-100 sec⁻¹,preferably 1-10 sec⁻¹.

According to one embodiment, the stable suspension is used for theproduction of a temperature-regulating, polymer comprising fabric.

According to another embodiment, the polymer is cellulose-based, thesolvent of the stable suspension comprises water and sodium hydroxide,the concentration of the sodium hydroxide ranges between about onepercent and about 8 percent by weight of the solvent and themicrocapsules form between about 15 percent and about 50 percent byweight of the suspension. According to a related embodiment, the polymeris cellulose-based, the solvent of the stable suspension comprises waterand sodium hydroxide, the concentration of the sodium hydroxide rangesbetween about 1.5 percent and about 3 percent by weight of the solventand the microcapsules form between about 15 percent and about 30 percentby weight of the suspension and the suspension is kept at an ambienttemperature.

Aspects also provide a fabric produced by a method using the stablesuspension. More specifically, the provided fabric may be a commercialproduct. According to one embodiment the fabric or commercial productcomprises a fiber or plurality of fibers.

According to another embodiment the stable suspension comprises at leastone additive selected from a group consisting of defoaming agents,flow-control agents, wetting and dispersing agents and surfactants, e.g.the ones listed above. Optionally, a suitable additive is present in thethird suspension, when used to provide the microcapsules. For example,the additive is used in the process of producing the microcapsules andremain in a suspension generated during that production, whichsuspension is used as the third suspension, as such or after somemodification. According to another embodiment, the additive is added assuch or in any combination, e.g. solution, to the provided components,e.g. the third suspension or the solvent prior to mixing, and/or addedafter mixing.

According to yet another embodiment, during mixing and/or after it, thestable (first) suspension is kept at a temperature in the range betweenabout ambient and about 120° C. According to another embodiment, duringmixing and/or after it, the stable suspension is kept under low-shearmixing.

According to another embodiment a method of manufacturing apolymer-containing temperature-regulating fabric comprises providing andincorporating at least one functional compound with functionalityselected from a group consisting of fire retardation, bioactivity,antimicrobial, odor resistance and UV absorption as describedhereinafter. According to one embodiment, functional compounds andfunctionality are selected from the group consisting of those set forthin Table 3. According to one embodiment, the functional compound isprovided in a dissolved form. According to another embodiment, thefunctional compound is encapsulated in shells. According to a relatedembodiment, the shell is similar in properties to the shells of thephase-change material microcapsules. According to another embodiment,the shell of the functional-compound microcapsules is made of the samematerial as the shell of phase-change material microcapsules. Any formof provided the functional material and/or its microcapsules issuitable, e.g. in the stable first solution or with the polymer and/orprecursor prior to combining those or after such combining.Incorporating the functional compound and/or its microcapsules may useany known method, e.g. mixing. According to another embodiment, thefunctional compound is encapsulated and its microcapsules are evenlydispersed in the second suspension. According to another embodiment, theformed second suspension comprises microcapsules of both phase-changematerial and functional compounds and both microcapsules are evenlydispersed in the second suspension. According to another embodiment thefunctional material is provided in the phase-change material-comprisingmicrocapsules.

According to another embodiment the method for manufacturing ofpolymer-containing temperature-regulating fabric comprises convertingthe second suspension, as such, or with additional components to thefabric. For example, the second suspension is coated by known methods onsurfaces, where it is further treated, e.g. evaporation of solvent,precipitation and/or polymerization of components included therein. Alsopossible is converting the second suspension into polymer pellets,wherein the microcapsules are evenly dispersed, which pellets is thenconverted to commercial products. The method for manufacturing ofpolymer-containing temperature-regulating fabric may also compriseconverting the second suspension into fiber. According to oneembodiment, the microcapsule-containing, phase-change material is evenlydispersed in the manufactured fiber.

Many fabrics are made from synthetic fibers. Conventionally, twoprocesses are used to manufacture synthetic fibers: a solution spinningprocess and a melt spinning process. The solution spinning process isgenerally used to form acrylic or regenerated cellulosic fibers, whilethe melt spinning process is generally used to form nylon fibers,polyester fibers, polypropylene fibers, and other similar types offibers. According to another embodiment the microcapsules-comprisingfiber is produced by the melt spinning process, wherein a molten polymerand microcapsules are provided, spun and cooled for solidification.Polymer pellets, wherein the microcapsules are evenly dispersed, areuseful for such fiber production via melt spinning. According to arelated embodiment, the shell of the microcapsules used for such meltspinning is made out of silica.

According to another embodiment the fiber is manufactured by means ofsolution spinning involving spinning a feed solution comprising polymerand/or polymer precursor, phase-change material-microcapsules andoptionally also at least one agent, surfactant or functional compound,as described above. According to another embodiment the feed solutionmay comprises the above-described second solution. According to anotherembodiment, a stable suspension is manufactured, as described above, andstored in a suitable first vessel at the above-specified temperaturerange and under the above-specified mixing. The amount of producedstable suspension is suitable for at least 20 hours of fiber production,preferably for at least 40 hours. A solution of the polymer and/orprecursor is also produced and kept in a second vessel. A feed solutionis generated by mixing a suspension from the first vessel with solutionfrom the second vessel, which is then spun through at least onespinneret and further treated, e.g. via, optionally polymerization, dryspinning or wet spinning. In the wet spinning process the spinnerets aresubmerged in or held very close to a chemical bath and as the filamentsemerge, they contact the chemical bath, and they precipitate fromsolution and solidify. In the dry spinning process instead ofprecipitating the polymer by dilution or chemical reaction,solidification is achieved by evaporating the solvent in a stream of airor inert gas. For more details, see Acrylic Fibers by R. Cox inSynthetic Fibers: Nylon, Polyester, Acrylic, Polyolefins, WoodheadPublishing ISBN 1 85573 488 1 and U.S. Pat. Nos. 5,686,034, 6,258,304,6,333,108 and 6,538,130, G.B. patent 2412083, and WO0231236, therelevant teaching of which is incorporated here by reference.

According to another embodiment the fiber is acrylonitrile-based.According to the embodiment, the solution in the second vessel ispreferably comprised of between about 5 and about 20 percent by weightsolute in a solvent. In other embodiments the solution in the vesselcomprises between about 10 and about 15 percent by weight solute insolvent. The solute, on a dry basis, is preferably made from betweenabout 80 and about 100 percent by weight of acrylonitrile monomer;between about 0 and about 20 percent by weight of neutral monomer, e.g.at least one of methyl acrylate, vinyl acetate, methyl methacrylate andacrylamide, and between about 0 and about 2 percent by weight of acidcomonomer, e.g. sodium styrene sulphonate, sodium methallyl sulphonate,sodium 2-methyl-2acrylamidopropane sulphonate and itaconic acid.

In other embodiments the solute, on a dry basis, is made from betweenabout 90 and about 95 percent by weight of acrylonitrile monomer andbetween about 0 and about 14 percent by weight of the neutral monomer.

According to another embodiment the fiber is a modacrylic fiber, theproportion is acrylonitrile in the solute is smaller and the solutecontains also another comonomer, typically halogenated ethylenicallyunsaturated molecules. The solvent of the solution in the second vessel,according to another embodiment, is an aqueous solution of sodiumthiocyanate, e.g. with sodium thiocyanate concentration in a rangebetween about 40 and about 60 percent by weight. According to anotherembodiment, e.g. in the case of modacrylic fiber, the solvent is asolution of acetone. That solution is prepared by known methods, such asdissolving the polymer by adding it slowly, with stirring, to coldsolvent and then raising the temperature to complete dissolution Thesolution in the second vessel is kept at a temperature of about ambient.

According to another embodiment the stable suspension in the firstvessel comprises an aqueous solution of sodium thiocyanate as a solvent.The concentration of the sodium thiocyanate in that solution is betweenabout 40 and about 60 percent by weight. The stable suspension comprisesmicrocapsules with a shell and a core, the shell forming between about 5and about 40 percent by weight of the microcapsules. The shell is madefrom a compound such as, silica and formaldehyde polymer. The corecomprises a phase-change material, e.g. a straight-chain or abranched-chain hydrocarbon with 15 to 25 carbon atoms. Typically, themicrocapsules are of a size (largest dimension) of up to about 2microns. The microcapsules form between about 5 and about 30 percent byweight of the suspension, which optionally also contains a viscositymodifier, e.g. as listed above. The stable suspension is prepared bygradually adding solvent to microcapsules suspension of about 50% inaqueous medium, while gently mixed. The stable suspension is kept in thefirst vessel at a temperature of about ambient under gentle low-shearmixing.

According to yet another embodiment, a feed solution is produced bymixing a solution from the second vessel with a suspension from thefirst vessel (optionally filtered) at a relative rate suitable to yielda concentration of 2-50% mPCM on polymer dry weight basis, morepreferably 5-20%. The feed solution is then spun by dry spinning or wetspinning (e.g. wherein the spinneret is submerged in or held very closeto a relatively dilute aqueous solution) to form acrylic fiberscontaining microcapsules with phase-change material. According toanother embodiment the fiber contains between about 5 and about 20percent by weight of evenly dispersed microcapsules. Those fibers arethen used for the production of various temperature-adaptable commercialproducts, such as woven fabrics, knit fabrics, and nonwoven fabrics,e.g. ones with enthalpy between about 1 J/g and about 50 J/g.

According to another embodiment the fiber is cellulose-based. Accordingto that embodiment, the solution in the second vessel is composed ofbetween about 5 and about 15 percent by weight solute in a solvent,preferably between about 8 and about 11 percent by weight. Thecomposition of the solute, on a dry basis, is between about 5 and about15 percent of the aqueous sodium hydroxide solution solvent. The solventof the solution in the second vessel is an aqueous solution of sodiumhydroxide, e.g. with sodium hydroxide concentration in a range betweenabout 4 and about 10 percent by weight. That solution is prepared byknown methods, such as dissolving the sodium hydroxide in water andadding cellulose. Preferably the dry cellulose is added with stirring,to prevent cellulose powder from sticking and forming clumps, to thecorrect amount of water and dissolved sodium hydroxide. This is thenstirred until the cellulose is dissolved and the solution is clear. Thesolution in the second vessel is kept at a temperature of about ambient

According to another embodiment the stable suspension in the firstvessel comprises an aqueous solution of sodium hydroxide as a solvent.The concentration of the sodium hydroxide in that solution is betweenabout 1 and about 5 percent by weight. According to another embodimentthe pH of the solvent is at least 10, preferably, at least 11.5. Thestable suspension comprises microcapsules with a shell and a core, theshell forming between about 5 and about 40 percent by weight of themicrocapsules. The shell is made from at least one compound such as,silica, acrylic acid, its derivative, methacrylic acid and itsderivatives. The core comprises a phase-change material, e.g. astraight-chain or a branched-chain hydrocarbon with 15 to 25 carbonatoms. Typically, the microcapsules are of a size (largest dimension) ofup to about 2 microns. The microcapsules form between about 10 and about50 percent by weight of the suspension, which optionally also contains aviscosity modifier, e.g. cellulose, cellulose derivatives, acidfunctional polymers, polyglycols, polysaccharide and polyvinyl alcohol.The stable suspension is prepared by gradually adding the solvent tomicrocapsules suspension of about 50% in an aqueous medium, while gentlymixed. The stable suspension is kept in the first vessel at an ambienttemperature, under gentle low-shear mixing.

According to another embodiment, a feed solution is produced by mixing asolution from the second vessel with a suspension from the first sample(optionally filtered) at a relative rate suitable to yield the desired %of mPCM on cellulose. The feed solution is then spun by dry spinning orwet spinning (e.g. by spinnerets submerged in or held very close to asolution of an acid, e.g. sulfuric acid) to form rayon or viscose fibercomprising microcapsules with phase-change material. According toanother embodiment the fiber contains between about 5 and about 40percent by weight of evenly dispersed microcapsules. Those fibers isthen used for the production of various temperature-adaptable commercialproducts, such as woven fabrics, knit fabrics, and nonwoven fabrics,e.g. ones with enthalpy between about 1 J/g and about 50 J/g.

While aspects of the invention will now be described in connection withcertain embodiments in the following examples and with reference to theaccompanying figures so that aspects thereof may be more fullyunderstood and appreciated, it is not intended to limit the scope of theinvention to these particular embodiments. On the contrary, it isintended to cover all alternatives, modifications and equivalents as maybe included within the scope defined by the appended claims. Thus, thefollowing examples which include various embodiments will serve toillustrate the practice of aspects described herein, it being understoodthat the particulars shown are by way of example and for purposes ofillustrative discussion of various embodiments only and are presented inthe cause of providing what is believed to be the most useful andreadily understood description of formulation procedures as well as ofthe principles and conceptual aspects.

Example 1 Stable Suspension of mPCM for Acrylic Fibers

To 100.0 kilograms of formaldehyde-based shell microcapsules(microencapsulated n-hydrocarbons, 115 J/g latent heat, 50 percentmicrocapsules, available from Ciba Specialty Chemical Co., Bradford,United Kingdom) is added with stirring 121.5 kilograms of water then178.5 kilograms sodium thiocyanate. This yields a stable suspensioncontaining 12.5% microcapsules with a sodium thiocyanate:water ratio of51/49. This suspension of microcapsules is stable againstagglomeration >21 hours.

Example 2 Stable Suspension of mPCM for Acrylic Fibers

To 100.0 kilograms of formaldehyde-based shell microcapsules(microencapsulated n-hydrocarbons, 115 J/g latent heat, 50 percentmicrocapsules, available from Ciba Specialty Chemical Co., Bradford,United Kingdom) is added with stirring a premixed solution of 121.5kilograms of water and 178.5 kilograms sodium thiocyanate. This yields astable suspension containing 12.5% microcapsules with a sodiumthiocyanate:water ratio of 51/49. This suspension of microcapsules isstable against agglomeration >21 hours.

Example 3 Stable Suspension of mPCM for Rayon, Viscose or CelluloseFibers

To 100.0 kilograms of polyacrylic shell microcapsules (microencapsulatedoctadecane, 175 J/g latent heat, 45 percent microcapsules, availablefrom Ciba Specialty Chemical Co., Bradford, United Kingdom) is addedwith stirring 100.0 kilograms of water, then 5.2 kilograms of a 50%NaOH/Water solution. This yields a stable suspension containing 21.95%microcapsules at a pH of 12.8. This suspension of microcapsules isstable against agglomeration >24 hours as shown by original slurryparticle size distribution (FIG. 1) and after 24 hours (FIG. 2). As willbe noted, there is no significant difference between the distributionwhen the suspension is first formed and the distribution after 24 hours.This stable suspension provided for excellent spinning performance, noline stoppage over multiple days, no filter plugging or blockage and wasused to spin 1.7 dtex viscose fiber.

Example 4 Unstable Suspension of mPCM for Rayon, Viscose or CelluloseFibers

To 100.0 kilograms of polyacrylic shell microcapsules (microencapsulatedoctadecane, 175 J/g latent heat, 45 percent microcapsules, availablefrom Ciba Specialty Chemical Co., Bradford, United Kingdom) is addedwith stirring 81.8 kilograms of water, then 1.8 kilograms of a 50%NaOH/Water solution. This yields an unstable suspension containing 25.0%microcapsules at a pH of 9.5 This unstable suspension caused pressurebuildup, filter blockage and line shutdown after 20 min.

Example 5 Stable Suspension of mPCM for Lyocell Fibers

0.90 g of deionized water and 0.20 g of water-wetted microcapsulescontaining a phase-change material (microencapsulated paraffin PCM, 120J/g latent heat, 50 percent microcapsules, available from Ciba SpecialtyChemical Co., Bradford, United Kingdom) were combined in a 20 ml glassvial. Next, 8.00 g of N-methyl morpholine oxide solvent (97 percentNMMO, available from Aldrich Chemical Co., Milwaukee, Wis.) were addedto yield a solution with 1.1 percent by weight of mPCM solids. The vialwas placed in a 125° C. oven and periodically mixed until its contentswere homogenously mixed and the solvent is melted. This solution can beused immediately or it can be cooled/solidified for storage thenreheated. This cycle can be repeated numerous times.

Example 6 Stable Suspension of mPCM for Lyocell Fibers

0.90 g of deionized water and 0.20 g of water-wetted microcapsulescontaining a phase-change material (microencapsulated paraffin PCM, 120J/g latent heat, 50 percent microcapsules, available from Ciba SpecialtyChemical Co., Bradford, United Kingdom) were combined in a 20 ml glassvial. Next, 8.00 g of N-methyl morpholine oxide solvent (97 percentNMMO, available from Aldrich Chemical Co., Milwaukee, Wis.) and 0.90 gof microcrystalline cellulose (available from Aldrich Chemical Co.,Milwaukee, Wis.) were added to yield a solution with 10 percent byweight of solids. The solids included a 90/10 weight ratio ofcellulose/microcapsules containing the phase-change material. The vialwas placed in a 125° C. oven and periodically mixed until its contentswere homogenously mixed and melted. This solution can be usedimmediately or it can be cooled/solidified for storage then reheated.This cycle can be repeated numerous times.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrative examples and thatthe scope of the present invention may be embodied in other specificforms without departing from the essential attributes thereof, and it istherefore desired that the present embodiments and examples beconsidered in all respects as illustrative and not restrictive,reference being made to the appended claims, rather than to theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedtherein.

1-39. (canceled)
 40. A stable suspension for the production of atemperature-regulating, polymer-containing material, the suspensioncomprising a solvent and a plurality of microcapsules containing atleast one phase-change material, wherein the microcapsules are to beincorporated in the polymer-containing material, and wherein the stablesuspension is characterized in that: (i) the solvent is capable ofdissolving a fabric-forming component selected from the group consistingof at least one of the polymer and precursors thereof; and (ii) thesuspension is stable for at least about 20 hours.
 41. The suspension ofclaim 40, further characterized in that at least about 95% of themicrocapsules stay intact in the suspension for at least about 20 hours.42. The suspension of claim 40, wherein the material is formed from atleast one type of polymeric fiber.
 43. The suspension of claim 40,wherein the polymer is selected from the group consisting ofacrylonitrile-based polymers, cellulose-based polymers, polyester-basedpolymers, polyamide-based polymers and polyolefin based polymers. 44.The suspension of claim 40, wherein the solvent is an aqueous solution.45. The suspension of claim 40, further comprising at least one furthercomponent selected from the group consisting of a defoaming agent, aflow-control agent, a wetting agent, a dispersing agent and surfactant.46. The suspension of claim 44, wherein the aqueous solutions compriseat least one further component selected from the group consisting ofsodium bases, sodium thiocyanate, zinc chloride, n-methyl morpholineoxide, ammonia, copper sulfate, nitric acid, acetone, DMF and NMP. 47.The suspension of claim 40, wherein the microcapsules comprise a shelland a core and wherein the shell is formed from at least one componentselected from the group consisting of acrylic acid and derivativesthereof, methacrylic acid and derivatives thereof, formaldehyde,isocyanate, urea, carboxylic acid derivatives, silica precursor andgelatin.
 48. The suspension of claim 40, wherein the microcapsulescomprise a shell and a core and wherein the core comprises aphase-change material selected from the group consisting of octadecane,straight-chain hydrocarbons with 15 to 25 carbon atoms, andbranched-chain hydrocarbons with 15 to 25 carbon atoms.
 49. Thesuspension of claim 40, wherein the microcapsules comprise a shell and acore and the weight ratio between the shell and core is in the rangebetween about 0.5:9.5 and about 4:6.
 50. The suspension of claim 40,wherein the microcapsules form between about 5 and about 40 percent byweight of the suspension.
 51. The suspension of claim 40, wherein themicrocapsules have a maximum linear dimension ranging between about 0.1and about 20 micron.
 52. The suspension of claim 40, further comprisingat least one compound with functionality, the functionality beingselected from the group consisting of fire retardation, bioactivity,antimicrobial activity, odor resistance, UV absorption, moisturemanagement and resistance to water, grease, dirt and/or stain.
 53. Thesuspension of claim 40, wherein the polymer is acrylonitrile-based,wherein the solvent comprises water and sodium thiocyanate, wherein theconcentration of the sodium thiocyanate ranges between about 40 andabout 60 percent by weight of the solvent and wherein the microcapsulesform between about 5 and about 30 percent by weight of the suspension.54. The suspension of claim 40, wherein the polymer is cellulose-based,wherein the solvent comprises water and sodium hydroxide, wherein theconcentration of the sodium hydroxide ranges between about 1 percent andabout 5 percent and wherein the microcapsules form between about 5 andabout 30 percent of the suspension.
 55. The suspension of claim 40,further comprising at least one fabric-forming component selected fromthe group consisting of a polymer and a precursor thereof.
 56. A methodfor manufacturing a suspension comprising a solvent and a plurality ofmicrocapsules containing at least one phase-change material, the methodcomprising: providing microcapsules containing a phase-change material;providing a solvent capable of dissolving a fabric-forming componentselected from the group consisting of at least one of the polymer andprecursors thereof; and mixing the solvent and the microcapsules to formthe suspension.
 57. The method of claim 56 further comprising adding atleast one further component selected from the group consisting of adefoaming agent, a flow-control agent, a wetting agent, a dispersingagent and a surfactant.
 58. The method of claim 56, wherein themicrocapsules are provided as a separate suspension of microcapsules ina fluid.
 59. The method of claim 58, wherein the suspension ofmicrocapsules in a fluid is provided in a vessel and the solvent isadded to the microcapsules in the vessel to form the first suspension.60. The method of claim 58, wherein the viscosity of the suspension ofmicrocapsules in a fluid is in the range of between about 100 and about3000 cps.
 61. The method of claim 56, further comprising wet spinning ordry spinning the suspension.
 62. The method of claim 61, wherein thesuspension is spun to form fibers.
 63. The method of claim 62, whereinthe fibers are combined with other fibers to form a fabric.